1. Field of the Invention
The present invention relates to a duct type air conditioning apparatus which utilizes a variable air quantity control system capable of regulating temperature in each room independently of the other. Particularly, it relates to the duct type air conditioning apparatus having a controller in which a temperature schedule and other programs are inputted.
2. Discussion of Background
There has so far been known a centralized air-conditioning system which carries out air conditioning by distributing temperature-regulated air to each room through air duct. The conventional air conditioning system has various meritorious effects in comparison with a heat pump chiller/fan coil system, a package air-conditioner decentralized arrangement system and others from the viewpoint that it can easily incorporate a humidifier, a high performance filter, an external air introducing system and a total heat-exchanger, hence it is able to perform a high grade air conditioning operation. It can utilize the room space with high effectiveness because it is sufficient to form an outlet port and an intake port for the room to be air-conditioned, and it has the least disorder in its heat transporting system Therefore, such central air conditioning system has been used widely for the air conditioning of a large-sized building. Of various central air conditioning systems, the variable air quantity control system capable of carrying out the energy-saving operations (hereinafter, referred to as "VAV system" ) is capable of controlling temperature in a plurality of rooms, each having different heat load, independently of the other, is capable of stopping the air-conditioning operation in those rooms which are not in use, is also able to reduce the running cost of the air conditioning system by changing the power for the air blower in accordance with quantity of air to be blown out, and, at the same time is able to decrease the capacity of the heat source device by taking into consideration of the rate of its use.
There are several types in the VAV system. As one system, there is a system which uses a throttle type VAV unit, in which pressure in the duct which varys depending on the degree of opening of the dampers is detected, and the capacity of the air blower is controlled so as to bring the value of pressure to a certain predetermined level. Therefore, when the heat load in the room decreases (even when the air quantity becomes small, the temperature of the air within the duct is controlled at a constant level), the required performance of the heat source device becomes small and the power for the air blower is also decreased.
As conventional techniques adopting the throttle type VAV unit, there are known those as in the Japanese Examined Pat. Publication No. 47497/1985 and as shown in FIG. 2.10a in Manual of Refrigeration and Air-conditioning (new fourth edition, technique for application) published by Nippon Reito Kyokai.
FIG. 13 is a diagram showing the system of the conventional air conditioning apparatus. In FIG. 13, a reference numeral 1 designates rooms to be air-conditioned (in this case, four rooms are to be air-conditioned). A numeral 2 designates a room unit disposed in the ceiling of the building, and which is constructed with an air-filter 3, a heat exchanger 4 and an air blower 5. A main air duct 6 is connected to the air outlet port of the room unit 2, and four branch ducts 7 are diverged from the main air duct 6. A throttle type VAV unit 8 is placed in each of the branch ducts 7. A damper 9 is turnably fitted within each of the VAV unit 8, and which is driven by a stepping motor (not shown). An outlet port 10 is provided at the end part of the branch duct 7. An inlet port 11 is provided at the lower part of a door in the room 1. An inlet port 12 is formed in the ceiling board above the corridor. An inlet duct 13 connects the inlet port 12 of the ceiling to the air inlet port of the room unit 2. A room controller 14 is attached to each of the rooms 1. A temperature detector 15 and a pressure detector 16 are disposed in the main air duct 6. A heat source device 17 such as a heat pump is connected to the heat exchanger 4. A controlling apparatus for controlling the operations of the heat source device, the air blower 5 and the dampers 9 is disposed in the ceiling.
In the conventional air conditioning apparatus having the construction as described above, when a user determines a set room temperature by the room controller 14 placed in each of the rooms, the degree of opening of the dampers is regulated at their optimum positions in accordance with the set room temperature for each room and the current temperature in each of the rooms. Pressure in the main air duct 6 varys depending on the degree of opening of the dampers 9. The pressure is detected by the pressure detector 16, and the capacity of the air blower 5 is changed so that a pre- determined established pressure is given. When the quantity of air blown is changed, the temperature of air at the outlet of the heat exchanger 4 is also changed. The temperature of the air is detected by the temperature detector 15 whereby the performance of the heat source device 17 is controlled so that a predetermined temperature of the air is given. Thus, the air regulated at a substantially constant temperature is blown into the rooms at flow rates depending on the magnitude of the heat load in each of the rooms. After the air-conditioning, the air in the rooms flows through the inlet port 11, the corridor, the inlet port 12 formed in the ceiling and the inlet duct 13 to be returned to the room unit 2. Such a series of control is carried out in the optimum manner by means of the controlling apparatus 18 so as to satisfy energy-saving and comfortableness on the basis of the detecting signals from the room controllers 14, the temperature detector 15, the pressure detector 16 and the various detectors (not shown) in the heat source device 17.
In the conventional air conditioning apparatus, however, a controlling operation in which the energy-saving and comfortableness are both satisfied has been insufficient. The reason is as follows. The conventional air conditioning apparatus adopting the VAV system has been used mainly for office buildings. In this case, the air conditioning apparatus is operated in the daytime in which each room is air-conditioned under substantially equal temperature condition, and its operation is stopped in holidays such as the weekends Accordingly, the function to adjust the air quantity by the VAV unit is merely to maintain a room temperature in each of the rooms at constant level by increasing or decreasing the flow rates depending on the heat loads changing due to the orientation of the rooms, the number of persons in the rooms and so on. In the conventional air conditioning apparatus, a program for operating the apparatus in given time zones and the stop of the operation in holidays is given to the controlling apparatus 18. In this case, the operation of air-conditioning for the room which is not in use can be stopped by the room controllers in the rooms.
There are many problems in the conventional air conditioning apparatus using the VAV system when it is applied to a private house. While energy can be greatly reduced by suitably controlling the apparatus, comfortableness for living may be impaired, or the operation of the apparatus becomes complicated and troublesome. For houses in U.S.A., duct type centralized air-conditioning systems are widely used. However, an air conditioning apparatus with automatic control of the VAV system is not practically used, and what is proposed is such a type that the degree of opening of the dampers is adjusted manually or by use of thermostats, or a set back value is used in certain time zones for a set temperature for the total system by using a timer. In the specification, "set back" means that when room warming operation is carried out, the set room temperature is shifted to a slightly lower value in the period of certain time, and when room cooling operation is carried out, it is shifted to a slightly higher level, thereby to save energy.
The conventional air conditioning apparatus is usually operated for all day and for all rooms. However, increase in the cost of energy in the recent years has increased the economic burden of the users and therefore, a system capable of saving energy is expected. Even though the conventional system accomplishes some amount of energy-saving by using the set back values, it can not greatly reduce the energy because of the lack of the function of a zoning control (namely, feeding of air is stopped to a room which does not require the air-conditioning). Further, the conventional air conditioning apparatus has the problems that it is troublesome to adjust the degree of the dampers, or open and close them by manual operations; efficiency of the apparatus decreases, and noise is increased because control of the capacity of the heat source apparatus and the air blower is not in association with the change of the air-flow rate.
Thus, the air conditioning apparatus adopting the VAV system is considered to be suitable for energy-saving in private houses. In this case, however, a special care is needed to save energy for each room. It is, therefore necessary to use a controller in which temperature schedules for the rooms are inputted. In this case, there is a problem that even though a program of temperature schedule is prepared so as to be in conformity with the life pattern of a family, the daily life is not always coincident with the actual life pattern. Therefore, it is necessary to easily change the program including data initially inputted.
Briefly, the following prior art problems need to be addressed:
(1) A life pattern in the weekdays is different from that in the holidays.
(2) Actual life is not always coincident with the life pattern inputted in the controller.
(3) In the case that a room is frequently opened and closed, the temperature difference between the interior and the exterior of the room should be small, and the temperature in the room should reach a predetermined value as soon as possible
(4) The zoning and the setting-back should realize remarkable energy-saving.
(5) The zoning and the setting-back should not impair comfortableness in the room.
(6) Operations of inputting and changing data should be simple.
As a controller used for an air conditioning apparatus for many rooms, there is known one as shown in Japanese Examined Utility Model Publication No. 8581/1985. The proposed air conditioning apparatus is of a type having a refrigerant piping instead of the duct type. In the published air conditioning apparatus, a plurality of room controllers and a main controller which functions as the room controllers are provided Accordingly, a set room temperature of any room can be changed by the main controller However, the air conditioning apparatus is not adapted to input a program for the temperature schedule and it is insufficient from the viewpoint of saving energy.